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EFFECTS OF ON-BOTTOM OYSTER MARICULTURE ON SMALL, SEDIMENT-DWELLING INVERTEBRATES
Ferraro, S P. AND F A. Cole. EFFECTS OF ON-BOTTOM OYSTER MARICULTURE ON SMALL, SEDIMENT-DWELLING INVERTEBRATES. Presented at Alaska Aquaculture Conference, Anchorage, AK, November 13-14, 2001.
As part of a programmatic effort to determine estuarine habitat values for ecological risk assessments, quantitative field studies of small ( 0.5 mm), sediment-dwelling invertebrates were conducted in Willapa Bay, WA in July 1998 and Tillamook Bay, OR in July 1999. The six habitats included in both studies were (1) "growout" (2-3 year old) oyster ground culture, (2) eelgrass, Zostera marina, (3) mud shrimp, Upogebia pugettenis, (4) ghost shrimp, Neotrypaea californiensis, (5) bare mud, and (6) subtidal, undredged. About fifteen 0.01 m2 ? 5-cm deep, 0.5 mm mesh samples were collected randomly in each habitat throughout both estuaries. Species lists and multivariate analyses of the data revealed that the benthic invertebrate community on oyster grounds was much more similar to that in eelgrass and mud shrimp habitat than that in ghost shrimp, bare mud and subtidal habitat. Among the six habitats studied, oyster grounds consistently ranked either first or second in terms of the number of species, numerical abundance, and total biomass of small benthic invertebrates. Oyster grounds, which have high economic value in terms of oyster production, therefore, are also ecologically valuable as they provide a superior habitat for small invertebrates upon which many ecologically and/or economically important higher trophic-level animals (e.g., fish, crabs, waterfowl) feed.